Reducing Incidents in Microservices by Repaying Architectural Technical Debt

Introduction: Architectural technical debt (ATD) may create a substantial extra effort in software development, which is called interest. There is little evidence about whether repaying ATD in microservices reduces such interest. Objectives: We wanted to conduct a first study on investigating the effect of removing ATD on the occurrence of incidents in a microservices architecture. Method: We conducted a quantitative and qualitative case study of a project with approximately 1000 microservices in a large, international financing services company. We measured and compared the number of software incidents of different categories before and after repaying ATD. Results: The total number of incidents was reduced by 84%, and the numbers of critical- and high-priority incidents were both reduced by approximately 90% after the architectural refactoring. The number of incidents in the architecture with the ATD was mainly constant over time, but we observed a slight increase of low priority incidents related to inaccessibility and the environment in the architecture without the ATD. Conclusion: This study shows evidence that refactoring ATDs, such as lack of communication standards, poor management of dead-letter queues, and the use of inadequate technologies in microservices, reduces the number of critical- and high-priority incidents and, thus, part of its interest, although some low priority incidents may increase.